Children have been used in vaccine research since its very beginning, usually said to have been in 1796, when Edward Jenner inoculated 8-year-old James Phipps with cowpox, and then challenged young James with actual smallpox (1). However, earlier, in 1789, Jenner inoculated his own 10-month-old son, Edward Jr., with swinepox. Edward Jr. then came down with a pox disease, which he fortunately recovered from. His father then challenged him with smallpox.

Edward Jr. survived his exposure to smallpox. But, since Edward Sr. wanted to determine the duration of young Edward’s protection, he again challenged his son with smallpox in 1791, when the boy was two. Edward Sr. inoculated his son yet again with smallpox when the boy was three. Fortunately, young Edward was resistant to each of the smallpox challenges his father subjected him to.

Jenner used several other young children in his experiments, including his second son, Robert, who was 11-months-old at the time. One of the children in Jenner’s experiments died from a fever; possibly caused by a microbial contaminant in an inoculum. [Microbes were not known in the late 18th century.]

We have no record of how Jenner (or his wife) felt about his use of his own children. However, there is reason to believe that Jenner felt some remorse over his use of James Phipps, who he referred to as “poor James.” Jenner looked after Phipps in later years, eventually building a cottage for him; even planting flowers in front of it himself.

By the 20th century, some of the most esteemed medical researchers were using children—in institutions for the mentally deficient—to test new drugs, vaccines, and even surgical procedures. These institutions were typically underfunded and understaffed. Several of them were cited for neglecting and abusing their residents. Moreover, their young patients were usually from poor families, or were orphans, or were abandoned. Thus, many of the children had no one to look out for their interests. In addition, research at these institutions was hidden from the public. [The goings-on at these institutions were, in general, hidden from the public, and most of the public likely preferred it that way.] Federal regulations that might have protected the children were not yet in existence, and federal approval was not even required to test vaccines and drugs.

In the early 1940s, Werner Henle, of the University of Pennsylvania, used children at Pennhurst—a Pennsylvania facility for the mentally deficient—in his research to develop an influenza vaccine. [Pennhurst was eventually infamous for its inadequate staffing, and for neglecting and abusing its patients (2). It was closed in 1987, after two decades of federal legal actions.] Henle would inoculate his subjects with the vaccine, and then expose them to influenza, using an oxygen mask fitted to their faces.

Pennhurst, a state-funded Pennsylvania facility for the mentally deficient, was one of the most shameful examples of the neglect and mistreatment that was common at these institutions. It was the site of Werner Henle’s research in the 1940s to develop an influenza vaccine.

Henle’s vaccine did not protect all of his subjects. Moreover, it frequently caused side effects. Additionally, Henle maintained (correctly?) that a proper test of a vaccine must include a control group (i.e., a group exposed to the virus, but not to the vaccine). Thus, he deliberately exposed unvaccinated children to influenza. Children who contracted influenza had fevers as high as 104o F, as well as typical flu-like aches and pains.

Despite Henle’s investigations at Pennhuerst, he was a highly renowned virologist, best known for his later research on Epstein Barr virus. See Aside 1.

[Aside 1: While Henle was researching his influenza vaccine at Pennhurst, Jonas Salk concurrently worked on an influenza vaccine, using adult residents (ranging in age from 20 to 70 years) at the Ypsilanti State School in Michigan.]

Next, consider Hilary Koprowski, an early competitor of Jonas Salk and Albert Sabin in the race to develop a polio vaccine (3). By 1950, Koprowski was ready to test his live polio vaccine in people. [That was four years before Sabin would be ready to do the same with his live polio vaccine.] Koprowski had already found that his vaccine protected chimpanzees against polio virus. And, he also tested his vaccine on himself. Since neither he nor the chimpanzees suffered any ill effects, Koprowski proceeded to test his vaccine on 20 children at Letchworth Village for mentally disabled children, in Rockland County, NY. [Like Pennhurst, Letchworth Village too was cited for inadequately caring for its residents.] Seventeen of Koprowski’s inoculated children developed antibodies to the virus, and none developed complications.

Koprowski did not initiate his association with Letchworth. Actually, Letchworth administrators, fearing an outbreak of polio at the facility, approached Koprowski, requesting that he vaccinate the children. Koprowski gave each child “a tablespoon of infectious material” in half a glass of chocolate milk (4). Koprowski never deliberately infected the Letchworth children with virulent virus.

Koprowski reported the results of his Letchworth studies at a 1951 conference of major polio researchers, attended by both Salk and Sabin. When Koprowski announced that he actually had tested a live vaccine in children, many conferees were stunned, even horrified. Sabin shouted out: “Why did you do it? Why? Why (4)?” See Aside 2.

[Aside 2: In the 1930s, Canadian scientist Maurice Brodie tested a killed polio vaccine in twelve children, who supposedly had been “volunteered by their parents (4).” For a short time Brodie was hailed as a hero. However, too little was known at the time for Brodie to ensure that his formaldehyde treatment had sufficiently inactivated the live polio virus. Consequently, Brodie’s vaccine actually caused polio in several of the children. After this incident, most polio researchers could not conceive of ever again testing a polio vaccine, much less a live one, in children.]

Neither Koprowski nor Letchworth Village administrators notified New York State officials about the tests. Approval from the state would seem to have been required, since Koprowski later admitted that he was certain he would have been turned down. And, it is not clear whether Koprowski or the school ever got consent from the parents to use their children. However, recall there were not yet any federal regulations that required them to do so.

Koprowski was untroubled by the uproar over his use of the Letchworth children, arguing that his experiments were necessary. Yet he later acknowledged: “if we did such a thing now we’d be put on jail…” But, he added, “If Jenner or Pasteur or Theiler (see Aside 2) or myself had to repeat and test our discoveries [today], there would be no smallpox vaccine, no rabies vaccine, no yellow fever vaccine, and no live oral polio vaccine.” Moreover, he maintained that, secret or not, his use of the Letchworth children fit well within the boundaries of accepted scientific practice.

[Aside 2: Nobel laureate Max Theiler developed a vaccine against yellow fever in 1937; the first successful live vaccine of any kind (5). Theiler formulated a test for the efficacy of his vaccine, which did not involve exposing humans to virulent virus. Sera from vaccinated human subjects were injected into mice, which were then challenged with the Yellow Fever virus.]

Koprowski referred to the Letchworth children as “volunteers (6).” This prompted the British journal The Lancet to write: “One of the reasons for the richness of the English language is that the meaning of some words is continually changing. Such a word is “volunteer.” We may yet read in a scientific journal that an experiment was carried out with twenty volunteer mice, and that twenty other mice volunteered as controls.” See Aside 3.

[Aside 3: Koprowski was a relatively unknown scientist when he carried out his polio research at Letchworth. He later became a renowned virologist, having overseen the development of a rabies vaccine that is still used today, and having pioneered the use of therapeutic monoclonal antibodies. Yet, he is best remembered for developing the world’s first effective polio vaccine; several years before Salk and Sabin brought out their vaccines.

Most readers of the blog are aware that the Salk and Sabin vaccines are credited with having made the world virtually polio-free. What then became of Koprowski’s vaccine? Although it was used on four continents, it was never licensed in the United States. A small field trial of Koprowski’s vaccine in 1956, in Belfast, showed that its attenuated virus could revert to a virulent form after inoculation into humans. Yet a 1958 test, in nearly a quarter million people in the Belgian Congo, showed that the vaccine was safe and effective. Regardless, the vaccine’s fate was sealed in 1960, when the U.S. Surgeon General rejected it on safety grounds, while approving the safer Sabin vaccine. Personalities and politics may well have played a role in that decision (3, 4).

Interestingly, Sabin developed his vaccine from a partially attenuated polio virus stock that he received from Koprowski. It happened as follows. In the early 1950s, when Koprowski’s polio research was further along than Sabin’s, Sabin approached Koprowski with the suggestion that they might exchange virus samples. Koprowski generously sent Sabin his samples, but Sabin never reciprocated.

Koprowski liked to say: “I introduce myself as the developer of the Sabin poliomyelitis vaccine (7).” He and Sabin had a sometimes heated adversarial relationship during the time when their vaccines were in competition. But they later became friends.]

Sabin was at last ready to test his polio vaccine in people during the winter of 1954-1955. Thirty adult prisoners, at a federal prison in Chillicothe, Ohio, were the subjects for that first test in humans. [The use of prisoners also raises ethical concerns.]

Recall Sabin’s public outcry in 1951 when Koprowski announced that he used institutionalized children to test his polio vaccine. In 1954, Sabin sought permission to do the very same himself; asserting to New York state officials: “Mentally defective children, who are under constant observation in an institution over long periods of time, offer the best opportunity for the careful and prolonged follow-up studies…”

Although Sabin had already tested his attenuated viruses in adult humans (prisoners), as well as in monkeys and chimpanzees, the National Foundation for Infantile Paralysis, which funded polio research in the pre-NIH days of the 1950s, blocked his proposal to use institutionalized children. Thus, Sabin again used adult prisoners at the federal prison in Ohio. With the concurrence of prison officials, virtually every inmate over 21 years-old “volunteered,” in exchange for $25 each, and a possible reduction in sentence. None of the prisoners in the study became ill, while all developed antibodies against polio virus.

Testing in children was still a necessary step before a polio vaccine could be administered to children on a widespread basis. But, Sabin’s vaccine could not be tested in children in the United States. Millions of American children had already received the killed Salk vaccine, and the National Foundation for Infantile Paralysis was not about to support another massive field trial of a vaccine, in children, in the United States (3).

Then, in 1959, after a succession of improbable events, 10 million children in the Soviet Union were vaccinated with Sabin’s vaccine (3). The Soviets were so pleased with the results of that massive trial that they next vaccinated all seventy-seven million Soviet citizens under 20 years-of-age with the Sabin vaccine. That figure vastly exceeded the number of individuals in the United States, who were vaccinated with the rival Salk vaccine during its field trials.

Next up, we have Nobel laureate John Enders who, in the 1950’s, oversaw the development of the first measles vaccine. Enders and co-workers carried out several trials of their attenuated measles vaccine; first in monkeys and then in themselves. Since the vaccine induced an increase in measles antibody titers, while causing no ill effects, they next tested it in severely handicapped children at the Walter E. Fernald State School near Waltham, Massachusetts.

Enders seemed somewhat more sensitive than either Henle or Koprowski to the ethics of using institutionalized children. Samuel L. Katz, the physician on Enders’ team, personally explained the trial to every Fernald parent, and no child was given the vaccine without written parental consent. [Federal guidelines requiring that step still did not exist.] Also, no child was deliberately infected with virulent measles virus.

Katz personally examined each of the inoculated Fernald children every day. None of these children produced measles virus, while all of them developed elevated levels of anti-measles antibodies. Also, the Fernald School had been experiencing severe measles outbreaks before the Enders team vaccinated any of its children. But, when the next measles outbreak struck the school, all of the vaccinated children were totally protected.

In 1963, the Enders vaccine became the first measles vaccine to be licensed in the United States. Several years later it was further attenuated by Maurice Hilleman (8) and colleagues at Merck. In 1971, it was incorporated into the Merck MMR (measles, mumps, and rubella) vaccine. See Aside 4.

[Aside 4: Before Enders carried out his measles investigations he pioneered the growth of viruses in tissue culture. In 1949, Enders, and collaborators Thomas Weller and Frederick Robbins, showed that poliovirus could be cultivated in the laboratory. This development was crucial, allowing Salk and Sabin to grow a virtually unlimited amount of polio virus and, consequently, to develop their polio vaccines. In 1954, Enders, Weller, and Robbins were awarded the Nobel Prize for Physiology or Medicine for their polio virus work.]

It may surprise some readers that before the mid 1960s the so-called Nuremburg Code of 1947 comprised the only internationally recognized ethical guidelines for experimentation on human subjects. The Nuremburg Code was drawn up by an American military tribunal during the trial of 23 Nazi physicians and scientists for atrocities they committed while carrying out so-called “medical” experiments during World War II. [Sixteen of the 23 Nazis on trial at Nuremburg were convicted, and 7 of these were executed (see Note 1)].

The Nuremberg Code’s Directives for Human Experimentation contained strongly stated guidelines. Its tenets included the need to obtain informed consent (interpreted by some to prohibit research using children), the need to minimize the risks to human subjects, and the need to insure that any risks are offset by potential benefits to society.

But, despite the well-articulated principles of the Nuremberg Code, it had little effect on research conduct in the United States. Federal rules, with the authority to regulate research conduct, would be needed for that. So, how did our current federal oversight of research come to be?

A 1996 paper in the The New England Journal of Medicine, “Ethics and Clinical Research,” by physician Henry Beecher, brought to the fore the need for rules to protect human subjects in biomedical research (9). Beecher was roused to write the paper in part by the early 1960s experiments of Saul Krugman, an infectious disease expert at NYU. Krugman used mentally deficient children at the Willowbrook State School in Staten Island, New York, to show that hepatitis A and hepatitis B are distinct diseases (9). Also, before a hepatitis vaccine was available, Krugman inoculated the children with serum from convalescing individuals, to ask whether that serum might protect the children against hepatitis. Krugman exposed the children to live virus either by injection, or via milkshakes seeded with feces from children with hepatitis.

Krugman found that convalescent sera indeed conferred passive immunity to hepatitis. Next, he discovered that by infecting passively protected patients with live hepatitis virus he could produce active immunity. Krugman had, in fact, developed the world’s first vaccine against hepatitis B virus (HBV) (see Aside 4). [Although Krugman used mentally deficient institutionalized children in his experiments, his investigations were nonetheless funded in part by a federal agency; the Armed Forces Epidemiology Section of the U.S. Surgeon General’s Office.]

[Aside 4: The first hepatitis B vaccine licensed for widespread use was developed at Merck, based on principles put forward by Nobel Laureate Baruch Blumberg, (10).]

Beecher was particularly troubled by two aspects of Krugman’s experiments. First, Krugman infected healthy children with live virulent virus. Beecher maintained that it is morally unacceptable to deliberately infect any individual with an infectious agent, irrespective of the potential benefits to society. [See reference 11 for an alternative view. “The ethical issue is the harm done by the infection, not the mere fact of infection itself.”]

Second, Beecher charged that the Willowbrook School’s administrators coerced parents into allowing their children to be used in Krugman’s research. The circumstances were as follows. Because of overcrowding at the school, Willowbrook administrators closed admission via the usual route. However, space was still available in a separate hepatitis research building, thereby enabling admission of additional children who might be used in the research.

Were the Willowbrook parents coerced into allowing their children to be used in the research there? Consider that the parents were poor and in desperate need of a means of providing care for their mentally impaired children. Making admission of the children contingent on allowing them to be used in the research might well be viewed as coercion. Yet even today, with federal guidelines now in place to protect human subjects, institutions such as the NIH Clinical Center admit patients who agree to participate in research programs. Is that coercion?

Beecher’s 1966 paper cited a total of 22 instances of medical research that Beecher claimed were unethical (9). Four examples involved research using children. Krugman’s work at Willowbrook was the only one of these four examples that involved vaccine research. Beecher’s other examples involved research using pregnant women, fetuses, and prisoners. But it was Beecher’s condemnation of Krugman’s hepatitis research at Willowbrook that is mainly credited with stirring debate over the ethics of using children in research.

Did Krugman deserve Beecher’s condemnation? Before Krugman began his investigations at Willowbrook, he plainly laid out his intentions in a 1958 paper in the New England Journal of Medicine (12). Importantly, Krugman listed a number of ethical considerations, which show that he did not undertake his Willowbrook investigations lightly. In fact, Krugman’s ethical considerations, together with his plans to minimize risks to the children, were not unlike the assurances one might now submit to an institutional review board (11).

Many (but not all) knowledgeable biomedical researchers claimed that Beecher misunderstood Krugman’s research and, thus, unjustly vilified him. Krugman was never officially censored for his Willowbrook investigations. Moreover, condemnation of Krugman did not prevent his election in 1972 to the presidency of the American Pediatric Society, or to his 1983 Lasker Public Service Award.

To Beecher’s credit, his 1966 paper was instrumental in raising awareness of the need to regulate research using human subjects. Beecher was especially concerned with the protection of children and, apropos that, the nature of informed consent.

In 1974, the National Research Act was signed into law, creating the National Commission for the Protection of Human Subjects of Biomedical and Behavioral Research. The basic ethical principles identified by the Commission are summarized in its so-called Belmont Report, issued in 1978. Its tenets include minimizing harm to all patients, and the need to especially protect those with “diminished autonomy” or who are incapable of “self-determination.” In addition, federal guidelines now require universities and other research institutions to have Institutional Review Boards to protect human subjects of biomedical research. [Reference 13 (available on line) contains a detailed history of the establishment of these policies.] See Aside 6.

[Aside 6: The infamous U.S. Public Health Service Tuskegee syphilis research program, conducted between 1932 and 1972, in which several hundred impoverished black men were improperly advised and never given appropriate treatment for their syphilis, also raised public awareness of the need to protect human subjects. More recently, research involving embryonic stem cells and fetuses has stoked an ongoing and heated public debate. Policies regarding this research are still not settled, with stem-cell research being legal in some states, and a crime in others. Other recent technological advances, such as DNA identification and shared databases, have been raising new concerns, such as the need to protect patient privacy. In response to these new developments, in June 2016, the US National Academies of Sciences,Engineering and Medicine released a report proposing new rules (indeed a complete overhaul of the 1978 Belmont Report) to deal with these circumstances. The Academy’s report has stirred debate in the biomedical community]

Note 1: The use of children in medical research makes many of us profoundly uneasy. We may be particularly troubled by accounts of the exploitation of institutionalized children, who comprised a uniquely defenseless part of society. Indeed, it was the very vulnerability of those children that made it possible for them to be exploited by researchers. Consequently, some readers may well be asking whether the activities of vaccine researchers Krugman, Koprowski, Sabin, Henle and others might have been comparable to that of the Nazis on trial at Nuremberg. So, I offer this cautionary interjection. While in no way condoning the vaccine researchers using institutionalized children, their work was carried out for the sole purpose of saving human lives. As Koprowski suggested above, if not for that work, we might not have vaccines against smallpox, rabies, yellow fever, and polio. Now, consider Josef Mengele, a Nazi medical officer at Auschwitz, and the most infamous of the Nazi physicians. [Mengele was discussed several times at Nuremberg, but was never actually tried. Allied forces were convinced at the time that he was dead, but he had escaped to South America.] At Auschwitz, Mengele conducted germ warfare “research” in which he would infect one twin with a disease such as typhus, and then transfuse that twin’s blood into the other twin. The first twin would be allowed to die, while the second twin would be killed so that the organs of the two children might then be compared. Mengele reputedly killed fourteen twin children in a single night via a chloroform injection to the heart. Moreover, he unnecessarily amputated limbs and he experimented on pregnant women before sending them to the Auschwitz gas chambers.

References:

Edward Jenner and the Smallpox Vaccine, Posted on the blog September 16, 2014.

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I am now a retired professor emeritus of Microbiology at the University of Massachusetts. Teaching virology has been a most rewarding aspect of my career. I especially enjoyed enlivening my lectures with a variety of relevant anecdotes.

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